Submission #120976

#	Time	Username	Problem	Language	Result	Execution time	Memory
120976		knon0501	Aliens (IOI16_aliens)	C++17	60 / 100	2057 ms	12024 KiB

aliens

#include "aliens.h"
#include <bits/stdc++.h>
using namespace std;
#define f first
#define s second
typedef pair<long long,long long> pp;
pp a[500005];
long long dp[500005];
pair<pp,int> ss[2][500005];
int nn;
pp aa[500005];
long long cc[500005];

inline long double cr(pp x,pp y){
    if(x.f==y.f)return 0;
    return (long double)(y.s-x.s)/(long double)(x.f-y.f);
}

long long take_photos(int n, int m, int k, std::vector<int> r, std::vector<int> c) {
    long long ans;

    int i,j;
    for(i=1 ; i<=n ; i++){
        a[i]={r[i-1],c[i-1]};
        if(a[i].s<a[i].f)swap(a[i].f,a[i].s);
    }
    sort(a+1,a+n+1);
    j=0;
    a[0].f=-1;
    a[0].s=-1;
    a[n+1].f=-1;
    for(i=1 ; i<=n ; i++){
        if(a[i].s<=a[j].s || a[i].f==a[i+1].f);
        else{
            aa[++nn]=a[i];
            j=i;
        }
    }
    n=nn;
  ///  cout<<n<<endl;
    int t=0;


    for(i=1 ; i<=n ; i++){
        dp[i]=(aa[i].s-aa[1].f+1)*(aa[i].s-aa[1].f+1);


        cc[i]=aa[i].f*aa[i].f-max((long long)0,aa[i-1].s-aa[i].f+1)*max((long long)0,aa[i-1].s-aa[i].f+1);
        cc[1]=aa[1].f*aa[1].f;
        while(t>=2 && cr(ss[1][t].f,ss[1][t-1].f)>=cr(ss[1][t-1].f,{-aa[i].f,dp[i-1]+cc[i]}))t--;
        if(t==1 && ss[1][t].f.s>=dp[i-1]+cc[i])t--;
        ss[1][++t]={{-aa[i].f,dp[i-1]+cc[i]},i};
       /// cout<<t<<"!@"<<endl;

    }

    ///cout<<cr(s[1][2].f,s[1][1].f)<<endl;
    int tt;
    ans=dp[n];
    for(int l=2 ; l<=k ; l++){
        j=1;
        tt=0;
        for(i=l ; i<=n ; i++){
            while(ss[1][j+1].s<=i && j<t && cr(ss[1][j].f,ss[1][j+1].f)<2*(aa[i].s+1))j++;
            dp[i]=(aa[i].s+1)*(aa[i].s+1)+ss[1][j].f.s+2*ss[1][j].f.f*(aa[i].s+1);


            pair<pp,int> w={{-aa[i].f,cc[i]+dp[i-1]},i};
            while(tt>=2 && cr(ss[0][tt].f,ss[0][tt-1].f)>=cr(ss[0][tt-1].f,w.f))tt--;
            if(tt==1 && ss[0][tt].f.s>=w.f.s)tt--;
            ss[0][++tt]=w;
        }
        for(i=1 ; i<=tt ; i++)ss[1][i]=ss[0][i];
        if(l<=n)
        ans=min(dp[n],ans);
        t=tt;
    }
    return ans;
}

• Subtask 1: 4 / 4
• Subtask 2: 12 / 12
• Subtask 3: 9 / 9
• Subtask 4: 16 / 16
• Subtask 5: 19 / 19
• Subtask 6: 0 / 40